Process for the recovery of nh3,so2,volatile organic acids and furfural from concentrated waste liquor

ABSTRACT

AMMONIA, FURFURAL, SULPHUR DIOXIDE AND VOLATILE ORGANIC ACIDS SUCH AS ACETIC AND FORMIC ACIDS ARE RECOVERED FROM AMMONIA BASED SULPHITE WASTE LIQUOR BY VOLATILIZING THEM, DRYING THE LIQUOR TO A POWDER, AND SEPARATING THEM FROM THE VOLATILIZED GASES.

United sfates 1 atent ()ce 3,810,81z Patenfed June 25, 1974 ABSTRAcT oETHE DISCLoSURE AInmonia, fuffufal, Su1phuf dioxide and volati1e ofganicacidS Such as acetic and fofmic acidS afo fecovefed ffom ammonia basedsulphite waste 1iquof by vo1ati1izing them, dfying the liquof to apowdof, and Sepafating then1 ffom the volatilizod gaSes.

BACKGRoUND oF THE fNvENTION Fiold of the Invention Tho invention felateSto a pfocess and appafatus fof the fecovefy of fof fufaL su1phufdioxido, ammonia, and vo1ati1e ofganic acids ffofn concontfated vvaste1iquof and paftioulaf1y to a pfoceSS and appafatus fof the fecovefy offuffufal, Sulphuf dioxide, aofnonia, fofmic acid, and acotic acfd ffofntho socaned Stfong liquof fofffled in the Sulphite of the seIni-pulpingpfocess and the evaIofation of conifefous of deciduouS Wood.

Desc fiption of the Pfiof Aft In the fechnical pu1pfng pfocess aconSfdofable paft of tho components of the Wood fs disso1ved in thocooking liqnid, foflT1ing vvaste liquof, Which is usuany fecovefed ffomtho waShing of pulp and concentfated by evapofa tion fof a latefbufning- Bufning of waste liquid Ineans, howevef, that a11 tho ofganiccofnponentS of the vvaste 1iquof afo lost and that only the ashes, Whichcontain the cooking alkali, and the sulphuf dioxido ffofn the sfnokegaSeS can be fecovofed. The aShes and the su1phuf diodde can then befenSed fof the pfepafation of the cooking 1iquid. As can bo seen ffomthe fonowing table, tho ofganic cofnponentS fofn1 the nlaiof paft of thedfy fnattef of the wasto Hquof.

The composions of the dfy mattef of tho waste 1iquof aftef sulphitecooking:

In pfoceSSes not containing a fecovefy of the cooking chen1icals, thoconcentfated Waste Hquof iS llS11a11y de- Stfoyed by bufning of it isdfied fufthof and n1afketed as a WaSte1iquof powdef. vvithout bufningtho vvaste 1iquof, tho fofmic acid and the acetic acid can bo focovefedby knoWn leaching pfocosses (e-g. sonoco). The Su1phuf df oxido and thefuffufa1 can be femoved by, fof oxamplo, tho knoWn stfipping pfocessos.If ammonia has been uSed aS tho cooking alkaH, the ammonia can befecoyefod by, fof exafnple, feleasing it ffom its sa1ts With a.stfongefalka1i and by st-fipping tho feloaSed ammonia, With, fof' exaInple,SteaIn. 1on exchango and dia1ytica1' pfocesSos have alSo beeneXpefifnented fof the fecovefy of aff1- nonia. A pyfolySiS of diluted ofconcentfated liquof can likewiso be used fof the fecovefy of ammonia.

The object of this invention is to cfeate a focess and an appafatus fofthe utilization of an the components of the waste liquof in a way Inofeeffective and econoInic than bufning.

SUMMARY oF THE INVENTION ccofding to the invention thefe is pfovided apfocess Whefein the chomicalS afe made volati1e, then the waSte H uof isdfied to a powdef and the volatile com ounds afe femoved and the volatHeofganic gaSes afe Sepafated ffom the uidS pfoduced in the dfying of thevvaste li uof.

BRIEF DESCRfPTION oF THE DRANGS FIGS. 14 inustfate, Schematicany, somepafticn1afly advantageouS appafatuseS fof tho caffying out of the pfocoss accofding to the invention.

DESCRIPfION oF THE P-RERERRED EMBoDIMENTS Tho waSte Hquof concentfate isconducted into an acidation and pfedistiHation feactof 1, into whichIninefa1 acid iS a1So conducted (FIG. 1). In addition to sulphufic acid,known as Such, Sul huf dioxide and hosphofic of ffftfic acid ofdiffefont acid mixtufes can be uSed as the minefa1 acid, the pufpose ofwhich is to felease the Sin1 ple fatty acids ffom theif salts. The useof Sulphuf di oxide in the acidation is advantageouS because it can bofecovefod fof use aS a cooking chemical latef in the pfoc ess. By 11singphosphofic and/of nitfic acid fof tho acida tion, a Waste-1iquof powdefis obtained in the subsequent dfying; this povvdef can be llsedadvantageous1y fof foddef of soi1ifnpfoving agent. In the aInfnoniufns111- phite pfocess, in pafticu1af, acidation is not necesSafilyfequifed because of tho abiHty of the ofganic acidS to diSSociateammonia Sa1tS thefInally, of the acidation can be caffied outadvantageously vvith the Said acidS of thoif fnixtufes. The acidatedconcentfate iS conducted into tho dfyef Z, fof Which foHef, vacuum,fufnace, Spfay, of othef dfyefS, 'Which afe known as Such and thetempefa tufo of Which can be contfoned, afe USed. The componentS Whichdo not evapofate at the dfying ten1pefatufe of the Waste nquof afefecovefed ffom the dfyef Z in the foffn of vvaste-Hquof povvdef. Theheat feleaSed iff the cooling of thiS poWdef is uSed moSt adVantageous1yfof the heating of the bufning aif of the bufnef of the dfyef. TheWaste-Houof poWdef iS used fof foddef, So0-ilnpfoving agent, Hgninpowdef of, altefnativoly, fof fueL T11e waSte gaSes obtained ffon1 thedfyef 2, Which, beSideS Watef-vapof, contain, anlong othef thingS, theacetic acid, the foffnio acid, tho fI1ffI1fal, the Sulphuf dioxide andtho aInmonia, afe condenSed in the condensef 3 by a known Inethod. ThofeleaSed heat iS used n1oSt advantageoUSly fof the feheating of thedfying gaSes. The acetic acid, fofn1ic acid, fuffufaL S11lphuf dioxide,and an1Inonia afe sepafated ffom each othef in a sepafating device 4Which contains sevefal unit opefations of cheInical technology, known aSSuch. Fof example, the fonowing method can be uSed. The fnffufa1 iSsepafated ffon1 the liquof by a knovvn pfocess if1c1lding distillationand evapofation op efations. T11e acetic acid and the fofmic acid afosepafated ffom the liquof by leaching opefationS known as such (e.g.ethyl acetate of fnethy1-ethy1ketone leaching) and sepafated ffom eachothef by azeotfopic distiHation knoWn aS Such, and pufified by knownmethods. Eithef the sulphuf dioxide iS Stfipped ffom the liquof by fnethodS known as Such and fetofned advantageously to the pfepafation of thocooking 1iql1id, of the liquof aS Such Wfth itS Su1phuf dioxido andammonia iS fetufned to the pfepafation of the cooking 1iquid. T11e saidunit opefationS can be caffied ont in anothef ofdef of be feplaced bysary in a11 caSeS.

In the ammonium Su1phite procesS, in pafticu1ar, de pend1ng on thedrying fenpefature, the 1`11I sa1ts of ofganic and Ininera1 acidS andthe 1111 con]poundS 111 genera1 can be nlade to diSSociate therInaHyan(1 t11uS Inove to the vvaSte gaS of the dTyeT without ac1dation. Thereleasing of the volatile acids is then pfon1oted by the other acidcomponentS of the vaSte liquof. In this caSe the acetic acid and theforInic acid can be fe1eaSed ffoIn their Sa1fS by acidating the vvaStegaSes ()f the dfyer of their condenSate with the Said acidS,paTticu1ar1y, With su1ph0r dioxide, Which can be advantageouS1y Teturnedto the prepafation of the cooking 1iqI1id. ESpeciany the yield offurfufa1 fecovered in the pfoceSS can be iTnproVed by conducting thewaSte 1iquor concentTate through a highten1pefature reactof 5 into thedfyeT 2 (FIC1, 3). T11e yie1d of the recoveTed furfura1 and the otherCheInicalS Tefefred t in th1S invention can be inlproved by Teusing thevvaSte gases of the dfyef aftel the Separation of the CheInica1S asdrying gas in the dryer; in this caSe the qua1ity of the waSte-1iquorpoWder is also improved since cafbonization is pTevented (FIGs. 2 and3). The SaIne TeSI11t is obtained if an inert gas, Such as nitr()gen, iS11sed aS the drying gaS in the dryef.

F1(}. 4 Shovvs a device With Which, for eXanp1e, the dfying ofan1n1oniun sl11phite vvaSte 1iqllor and the recovery of chen1icalS canbe carried ollt adVantageouSly by uSing a S Tay dryef as the dfyer. Thismode of prac0cing the proceSS of thiS invention adVantageously includeSthe step of pTeheating the waSte Hquor befofe drying it, I{eferencenumbefs 1s are the Same aS above, and the other nun1 befs Tefef to thefo11ovving 11nits:

0 0i1 burner, indirect fecovery of heat 5 preheating reactor, coo1ef ofSInoke gaseS 2 SpTay dTyer 7 fecovery of heat of drying gaSes intocifc111ating gaS 3 acidation Teactor 4 TecoVery of vo1at11e chenTiCa1sand condenSation of vVatervapor l 8 cooling of WaSte1iquor powder andpfeheating of burn ing aif A pre-evaporated vvaSte 1iquo1 B pTeheatedwaSte 1iqU0r N hot vvaSte-1iquof povvdef o cooled waSte-1iquof 1)oWdeI ScooHng air P burning ail R Smoke gaSes M heated drying (cifc111ating)gaS C WaSte gas of dTying (WateTvapof chemica1S) 1) co()1ed vvaste gasof dfying H acidation 'acid, e.g. Sulphur diOXide E acidated waste gas Fvo1ati1e organic acidS and fIIrfI1ra1 G condenSate and So and NH (NH Sofo1 the preparation of cooking 1iq11id K u0condenSed ciTcll1ating gaS Lpreheated ciTculating gas Q burning oi1 ,The proceSS according to theinvention is particu1ar1y advantageous in such su1phite processeS as donot inc1ude a Tecovery of cooking chen1ica1S, vVhen the aiIn is torecover a11 the va1uable coInponentS of the waste liq00f. The n1ostadvantageous Tes111t econOInicany iS obtained in the process in Whichdeciduous wood is cooked in a cooking 1iquid coI1taining an1Inonia aodsulphuT dioxide.

EXAMPLE 1 vVhen drying the vaSte Hquor of an aInInonium SU1phite 01111(favv fIlateTia1= b1Tch) in a device accofding 1 1(1. 1

of the chenica1S of fhe vva01e 1iquor vaS obtained= Wast0 00n, i uorPoWder denSate vv0ter 10 00 AInmon1a 100 00 10 Su1phu d10x1de 100 50 50Acetic acid 100 00 40 Sugars 100 100 0 EXAMPLE z vvhe0 the drying ofwaste Hquof accofding to EXample 1 WaS carTi0d out by using acids, thefoHowing diStTibu1ion of t11e cheInica1S of the waSte 1iquof vvasobtained= vvhen the drying according to ExaInp10 1 waS carr10d out at(1iffeTent teInperatuTeS,1he foHoWing disf ibutionS of the chemica1S ofthe waste Hq0id Were obtained Phosphoric aci0 acidation 0. 0000! P0Wderd0n at0 1t can be Seen ffoIn this eXaInp1e how the pentoSes (SIgarS)becoIne furfura1S and Inove to the condenSate of the dTyihggaSOS.vhen^1ho-dfy1ng fefhpofa10fo 1S Taised. 1-he dehydTation of thepentoSeS into furfura1 iS pTomoted by the Strong 1ignos01ph00ic acidSTeInaining in the powdeT.

= EXAMPLE 4 vVhen vvaSte 1iquor vvaS dTied in a device according to FIG.1 by uSingair as the drying gas and 111 a device according to 1=1C1. 2by llsing ciTc111at1ngWaSte gas of the dTying proceSS aS 1110 dTyinggaS, the feSpec11ve d1Str1bn tionS of the cheInicaIs into thecondenSateS vvere the fo1 1owing:

Phosphofic acid acidation, tenlperature Dry1ng g0s Cimu 10nng 1 ercent rg0S EXAMPLE S 1)epending on the nlateriaIs and dTying teInpeTatuTe uSedin the acidation, the waSte-Hquor powder is paT ticulaTly Suitabe forvarious pnT oSes, Such as= Dispersion, pigment for =aint. ueL GlueInotter.

vvhat iS claimed iS= 1. A proceSS fo1 manufactuTe and Tecovery ofchemicalS compriSing ammonia, fuTfUfaL Sulhpur dioxide, acetic acid, andforn]ic acid, from concentTated ammonia baSed sulphite vvaste liquor,coInprising volatilizing said chen1icalS and dfying the waste li uorinto a vvaste liquor concentTate at a tenl eTatUre of fIom about 110 to200 C., and Separating Said chemicalS fTom the uids pTo duced in thedrying of the vvaste li uor.

2. T'he proceSS of claim 1 WheTein an acid Selected ffom the groupconsisting of phosphoTic acid, 11itTic acid, SulphuTic acid and Sulphufdioxide is added to the waSte liquoT to conveTt any Salt of an organicvolatile acid i11to acid form.

3. The process of claim 1, WheTein the drying is ef fected at atempeTatUTe high enough to evapoTate am monia and decompoSe any ammoninmSalt of the oT ganic volatile acidS into volatile form.

4. The proceSS of claim 1, Wherein the drying iS offected at atemperatuTe high enough to effect dehydTation of the pentoSes of theSulphite Waste liquo1 into fuTfuraL 5. The process of claim 1, Whefeinthe non-condensed gases ffoII1 the sepaTation are Tecycled to the dtyingstep to pIomote the Tecovery of the chemicalS and impmve the uaHt of thedried waste1i uor oWdef,

o. The Tocess of claim 1, vvheTein the Waste H uor iS pTeheated befofedTying in ordel to promote the Tecovery of the cheInicals.

7. The pTocess of clain1 1, Wherein condenSate ftom the separating stepiS USed with the Sulphur dioxide and cooking alkali iI1 the condensatein the cooking of tho pulp.

8. The pTocesS of cla im l, WheTein condenSate ffom the separating Stepis used iI1 WaShing the pulp.

ReferenceS Ced UNITED STATES PATENTS 2,689,ZS0 9/19S4 Natta 260347.9

1,838,109 12/1931 Richter Z347,9

2,966,396 12/1960 Eaton 423356 FOREIGN PATENTS 494,611 10/1938GreatBritain 260347 9 0SCAR R. vERTT Prin1ar Examiner H. s. MILLER,ASSistant EXaminer U.s. CL X R.

Z60S14 R, 347.9; 4Z3S40

